201134107 六、發明說明： 【發明所屬之技術領域】 本發明係關於一種前端（front-end)電路，特別係關於一 種具有兩或多個信號路徑的前端電路。 【先前技術】 無線應用中有許多不同種類的元件。舉例而言，行動 電話、膝上型電腦、行動式裝置、智慧型手機和類似的裝 置均為可無線通訊的裝置並且可在不同形式的通訊方式中 使用無線應用。該些裝置常常包含不同通訊功能的多個接 收器。在多個接收器分享相同的無線電頻率輸入之無線装 置中’例如一天線和其相關聯的濾波器和/或開關是由多個 接收器所分享的裝置中’不同的接收器常常用於不同形式 的通訊系統，例如Wi-Fi、藍芽、GPS和類似裝置》 圖1顯示一傳統的雙接收器1〇之方塊示意圖。該雙接收 器1〇包含一接收器前端18。該接收器前端18耦合至多個（在 本範例中為兩個）接收器子系統2〇〇該接收器前端18包含一 天線12和一可程式化放大器14。該可程式化放大器14可經 调整以提供不同的放大增益給藉由該天線所接收的信號。 每一接收器子系統20包含混波器22a/22b。混波器22a和22b 個別耦接至放大器24a和24b，而放大器24a和24b個別提供 輸出信號26a和26b。 為了達到最佳的接收效果，例如靈敏度’複數個接收 器子系統20通常在前置放大器14後連接在一起，以最小化 由於信號分離的功率損失所造成的整體系統靈敏度之衰變 201134107 因為每一接收器子系統2〇準備接收的信號強度（通常在不 同的頻率下）並不相同’每一接收器子系統通常需要前置 放大器14不同的增益量。因此，共同的前端電路a較佳為 能同時提供每一接收器不同的放大量。然而，傳統的雙接 收器10無法達到此一要求。 一種習知用以最佳化雙接收效果的方法為對複數個接 收器之每一者作的設計，使得每一接收器子系統2〇能在固 定的前置放大器增益下容忍最大的可能輸入信號功率。 另一種習知方法是為所選擇的接收器的大輸入信號之 最佳化接收來調整前端增益。然而，在前置放大器的增益 對非優先的接收器太尚或太低時，兩接收器的另一者之效 月&通常會被衰減。 第二種習知方法是對兩接收器的運作進行分時 ⑴meshadng)處理，因此兩接收器的每一者可在其為主動狀 態時設定最佳的前端增益。然而，該方法的缺點是複數個 接收器子系統無法允許同時被使用。 據此，有必要對無線裝置中的複數個接收器子系統提 供一種有效率和低成本的方式，使每一接收器子系統可在 最佳的設定下運作。本發明於此強調此一需求。 【發明内容】 本發明揭示一種前端接收器。該前端接收器包含來自 一信號輸入端的複數個傳遞信號的路徑、複數個切換機制 和複數個接收子系統。該等傳遞信號的路徑中之至少一路 徑包含-第-放大器’而該第—放大器㈣至該等切換機 201134107 制中的每一者之一第一輸入痒。 其他路徑包含一第二放大器，而該號的路徑中之 切換機财的每_者之—第二輸—==器輕接至該等 每-者輕接至該等切換機制中的其中：=統二 一接收子系統控制該切換機制以選擇—路徑。該路徑取^ =:號輸入端所接收的信號強度以對無線電接收而言為 本發明揭示-種無線電接收器。該無線電接收器包含 一别端接收ϋ和-天線。該天線耦接於該前端接收器的輸 入端。該前端接收器包含來自—信號輸人端的複數個傳遞 W的路徑、複數個切換機制和複數個接收子系統。該等 傳遞信號的路徑中之至少一路徑包含一第一放大器，而該 第一放大器耦接至該等切換機制中的每一者之一第一輸入 埠。該等傳遞信號的路徑中之其他路徑包含一第二放大 器，而該第二放大器耦接至該等切換機制中的每一者之一 第二輸入埠。該等接收子系統之每一者耦接至該等切換機 制中的其中-者之-輸出埠。每_接收子系統控制該切換 機制以選擇一路徑。該路徑取決於該信號輸入端所接收的 信號強度以對無線電接收而言為最佳化。該等接收子系統 的輸出端耦接至至少一個解調器，藉以轉換一調變的信號 至數位形式或類比形式的基頻波形。 【實施方式】 本發明係關於一種前端電路，特別係關於一種具有雙 增益的前端電路。以下敘述之表示是為使本發明所屬技術 領域中具有通常知識者能瞭解其内容並可據以實施。較佳 201134107 實施例之不同修改和在此描述 ag ^ τΕ . 叙社原則和特點對於孰 S本項技術者而言為明顯的，丁於热 干之眚#/, _ 本發明不應受；限於所 不之實施例，而應基於上述 廣之範圍。 j和特點給予-致性的最寬 本發明揭示一種前端電路， ^ 具可使兩或多個接收琴可 依個別的最佳設定而運作，以幸 " 以違到最大化的動態範圍。 因此本發明之目的為提供_前端電路使得傳送到 每-接收器的最大信號功率可以控制在適當的範圍内。 本發明之另-目的為提供具有兩信號路徑的前端電 路。兩接收器的每—者選擇一路徑，其最佳化於接收器準 備處理的信號強度。換言之，兩個以上的接收器可分享相 同的前端電路（前置放大器），且仍可個別地選擇前級放大增 益，以最佳化地滿足每一獨立的接收器之動態範圍限制。 圖2繪不本發明第一實施例之前端結構1〇〇之示意圖。 該刖端結構100的輸入標記為"ANT" 102，其可為一天線。該 前端架構100包含一放大區1〇3,該放大區1〇3包含輕接於天 線102的放大器1〇4和106。該前端架構100另包含一切換機 制區105 ’該切換機制區1〇5包含兩切換機制1〇83和1〇8b。 該前端架構100包含一接收子系統區107。在本實施例中， 該接收子系統區10 7包含兩接收子系統。每一接收子系統包 含輕接於放大益112a的混波ll〇a或包含耗接於放大器 112b的混波器11 〇b。該些接收子系統的輸出個別標示為 "RX1"114a和"RX2"114b。 熟悉本項技術之人士可瞭解本發明之系統和方法不應 限制於圖2所示的兩接收器。本發明可應用於使用超過一個 201134107 接收器子系統的任何無線系統中，且其應用不背離本發明 之精神並為為隨後之申請專利範圍所涵蓋。 在本實施例中，放大器104具有比放大器106較高的增 益。放大器104和106可同時為主動狀態。 低增益放大器106具有一高輸入阻抗。因此，當兩放大 器104和106結合於輸入1〇2時，對高增益放大器1〇4而言僅 會有可以忽略的輸入信號功率降低。這對本發明的系統和 方法而言為一重要特點。由於放大器1〇6的低增益性質，對 熟悉本項技術之人士而言可輕易達成高輸入阻抗之設計。 圖5中的衰減器304為一設計範例。參照圖2，接收子系統區 107中的混波器ll〇a和ll〇b切換於放大器1〇4和106的輸出 之間’以允許接收器接收的信號保持在其動態範圍内。 該架構可能包含兩緩衝放大器（未搶出），其輸出藉由結 合器或是切換機制連接至其後的接收級之輸入。此處亦可 使用任何其他的可用開關。放大器1〇4和1〇6較佳地設計為 具有固定的放大增益。 使用上述前端結構，從共同輸入埠i 〇2接收信號的多個 接收器子系統可在前置放大器級中選擇不同的放大量，以 控制傳送至每一獨立的接收器子系統之輸入信號在特定的 接收益之動態範圍内。 圖3繪示本發明第二實施例之前端結構1〇〇，之示意圖。 該前端結構100·具有與圖2繪示的結構類似之元件，且該些 元件具有類似的標號。參照圖3，該前端結構〗包含第一 級142、第二級144和其他級146，其中第二級包含耦接至放 大器104,和106,的複數個放大器2〇2_2〇8。在本實施例中放 201134107 大器202和206耦接至放大器l〇4，，而放大器204和208耦接至 放大器106’。第二級144的輸出耦接至其後的接收級之輸入。 在一實施例中，第二級中的放大器A3至A6(202至208) 具有可調整的增益以提供額外的RF自動增益控制 (Automatic Gain Control，AGC)功能，該功能控制輸入功率 至對應的下一級（通常為降頻混波器1 i 〇ai和丨丨〇b，）。 使用上述前端結構，從共同輸入埠1〇2,接收信號的多個 接收器112a’和112b，可在前置放大器級中選擇不同的放大 量’以控制傳送至每一獨立的接收器U4a，和U4b，之輸入信 號在特定的接收器之動態範圍内。 圖4例示圖3中的第二級144之切換功能之運作方式。在 本實施例中，”尚增益輸入"端連接至高增益放大器，的輸 出，而’，低增益輸入"端連接至低增益放大器1〇6，的輸出。基 本電流源11(402)和電流源12(404)交替地導通以選擇高增益 路徑或低增益路徑’藉以實現切換功能。 圖5繪示本發明第三實施例之前端結構丨〇〇"之示意 圖。該前端結構1〇〇”具有與圖2繪示的.結構類似之元件，且 該些元件具有類似的標號。該前端結構1〇〇，，的不同點在於 在第三實施例中放大器3〇2a和302b是相同的。然而。放大 器302b的輸入藉由輸入端的衰減器3〇4而衰減，因而減少了 放大器302b的增益並增加了放大器3〇2b的高信號容忍度。 本發明另一實施例提供具有上述前端電路.的接收器。 根據本發明所揭示的系統和方法提供一無線電通訊接收 器，使得複數個接收器可以依個別最佳的設定而運作，以 達成最大化動態範圍。該系統和方法提供—前端電路，使 201134107BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front-end circuit, and more particularly to a front-end circuit having two or more signal paths. [Prior Art] There are many different kinds of components in wireless applications. For example, mobile phones, laptops, mobile devices, smart phones, and the like are all wirelessly communicable devices and can use wireless applications in different forms of communication. These devices often contain multiple receivers with different communication functions. In a wireless device where multiple receivers share the same radio frequency input 'eg an antenna and its associated filters and/or switches are shared by multiple receivers' different receivers are often used for different Forms of communication systems, such as Wi-Fi, Bluetooth, GPS, and the like. Figure 1 shows a block diagram of a conventional dual receiver. The dual receiver 1A includes a receiver front end 18. The receiver front end 18 is coupled to a plurality (two in this example) of a receiver subsystem 2 that includes an antenna 12 and a programmable amplifier 14. The programmable amplifier 14 can be adjusted to provide different amplification gains to signals received by the antenna. Each receiver subsystem 20 includes a mixer 22a/22b. The mixers 22a and 22b are individually coupled to the amplifiers 24a and 24b, while the amplifiers 24a and 24b individually provide output signals 26a and 26b. In order to achieve optimal reception, such as sensitivity, a plurality of receiver subsystems 20 are typically connected together after the preamplifier 14 to minimize the decay of the overall system sensitivity due to power loss of the signal separation 201134107 because each The signal strengths (usually at different frequencies) that the receiver subsystem 2 is ready to receive are not the same 'Each receiver subsystem typically requires a different amount of gain from the preamplifier 14. Therefore, the common front end circuit a preferably provides a different amount of amplification for each receiver at the same time. However, the conventional dual receiver 10 cannot meet this requirement. One conventional method for optimizing the dual receive effect is to design each of a plurality of receivers such that each receiver subsystem 2 can tolerate the largest possible input at a fixed preamplifier gain. Signal power. Another conventional method is to adjust the front end gain for optimal reception of the large input signal of the selected receiver. However, when the gain of the preamplifier is too low or too low for a non-prioritized receiver, the other of the two receivers is usually attenuated. The second conventional method is to perform time-division (1)meshadng processing on the operation of the two receivers, so that each of the two receivers can set the optimal front-end gain when it is active. However, the disadvantage of this method is that multiple receiver subsystems are not allowed to be used at the same time. Accordingly, it is necessary to provide an efficient and low cost way for a plurality of receiver subsystems in a wireless device to operate at a optimal setting for each receiver subsystem. The present invention emphasizes this need here. SUMMARY OF THE INVENTION A front end receiver is disclosed. The front end receiver includes a plurality of paths for transmitting signals from a signal input, a plurality of switching mechanisms, and a plurality of receiving subsystems. At least one of the paths of the transmitted signals includes a -first amplifier and the first amplifier (four) to one of the switches 201134107 is first input itch. The other path includes a second amplifier, and each of the switches in the path of the number is switched to the one of the switching mechanisms: = The unified receiving subsystem controls the switching mechanism to select the path. The path takes the strength of the signal received at the input of the ^ =: to the radio reception as disclosed in the present invention. The radio receiver includes an end receiving and an antenna. The antenna is coupled to an input end of the front end receiver. The front end receiver includes a plurality of paths for transmitting W from the signal input terminal, a plurality of switching mechanisms, and a plurality of receiving subsystems. At least one of the paths of the transmitted signals includes a first amplifier coupled to one of the first input ports of each of the switching mechanisms. The other of the paths of the transmitted signals includes a second amplifier coupled to one of the second switching ports of each of the switching mechanisms. Each of the receiving subsystems is coupled to one of the switching mechanisms. Each _ receiving subsystem controls the switching mechanism to select a path. The path is dependent on the signal strength received at the signal input to optimize for radio reception. The outputs of the receiving subsystems are coupled to at least one demodulator for converting a modulated signal to a digital form of a digital form or analog form. [Embodiment] The present invention relates to a front end circuit, and more particularly to a front end circuit having dual gain. The following description is made to enable those of ordinary skill in the art to which the invention pertains to understand the contents and practice. Preferably, the different modifications of the embodiment of 201134107 and the description of ag ^ τΕ are described herein. The principles and characteristics of the society are obvious to the technologist of the present invention, and the invention is not to be accepted; It is limited to the embodiments and should be based on the broad scope described above. The widest range of features and characteristics of the present invention The present invention discloses a front-end circuit that allows two or more receiving pianos to operate according to individual optimal settings for the sake of the maximum dynamic range. It is therefore an object of the present invention to provide a front end circuit such that the maximum signal power delivered to each receiver can be controlled within an appropriate range. Another object of the invention is to provide a front end circuit having two signal paths. Each of the two receivers selects a path that is optimized for the signal strength that the receiver is prepared to process. In other words, more than two receivers can share the same front-end circuitry (preamplifier) and the preamplifier gain can still be individually selected to optimally meet the dynamic range limits of each individual receiver. Fig. 2 is a schematic view showing the end structure 1〇〇 before the first embodiment of the present invention. The input of the terminal structure 100 is labeled "ANT" 102, which can be an antenna. The front end architecture 100 includes an amplification area 1〇3 that includes amplifiers 1〇4 and 106 that are lightly coupled to the antenna 102. The front end architecture 100 further includes a switching mechanism area 105'. The switching mechanism area 1〇5 includes two switching mechanisms 1〇83 and 1〇8b. The front end architecture 100 includes a receive subsystem area 107. In this embodiment, the receiving subsystem area 107 includes two receiving subsystems. Each receiving subsystem includes a mixing signal 〇a that is lightly coupled to the amplification benefit 112a or a mixer 11 〇b that is consuming the amplifier 112b. The outputs of these receiving subsystems are individually labeled "RX1"114a and "RX2"114b. Those skilled in the art will appreciate that the system and method of the present invention should not be limited to the two receivers shown in FIG. The present invention is applicable to any wireless system using more than one 201134107 receiver subsystem, and its application does not depart from the spirit of the present invention and is covered by the scope of the subsequent patent application. In this embodiment, amplifier 104 has a higher gain than amplifier 106. Amplifiers 104 and 106 can be active at the same time. The low gain amplifier 106 has a high input impedance. Therefore, when the two amplifiers 104 and 106 are coupled to the input 1〇2, there is only a negligible input signal power reduction for the high gain amplifier 1〇4. This is an important feature for the systems and methods of the present invention. Due to the low gain nature of the amplifiers 〇6, high input impedance designs can be easily achieved by those skilled in the art. The attenuator 304 in FIG. 5 is a design example. Referring to Figure 2, the mixers 110a and 11b in the receive subsystem region 107 are switched between the outputs of the amplifiers 1 and 4 to allow the signals received by the receiver to remain within their dynamic range. The architecture may contain two buffer amplifiers (not robbed) whose output is connected to the input of the subsequent receive stage by a combiner or switching mechanism. Any other available switches can also be used here. The amplifiers 1〇4 and 1〇6 are preferably designed to have a fixed amplification gain. Using the front-end structure described above, multiple receiver subsystems that receive signals from the common input 埠i 〇2 can select different amplification levels in the preamplifier stage to control the input signals transmitted to each of the individual receiver subsystems. Within the dynamic range of specific receiving benefits. 3 is a schematic view showing the front end structure 1 of the second embodiment of the present invention. The front end structure 100 has elements similar to those shown in Fig. 2, and the elements have similar reference numerals. Referring to FIG. 3, the front end structure includes a first stage 142, a second stage 144, and other stages 146, wherein the second stage includes a plurality of amplifiers 2〇2_2〇8 coupled to the amplifiers 104, and 106. In the present embodiment, the 201134107 amplifiers 202 and 206 are coupled to the amplifier 104, and the amplifiers 204 and 208 are coupled to the amplifier 106'. The output of the second stage 144 is coupled to the input of the subsequent receive stage. In an embodiment, amplifiers A3 through A6 (202 through 208) in the second stage have adjustable gains to provide additional RF Automatic Gain Control (AGC) functionality that controls the input power to the corresponding The next level (usually the down-converter 1 i 〇ai and 丨丨〇b,). Using the front-end structure described above, from the common input 埠1〇2, the plurality of receivers 112a' and 112b receiving the signals can select different amplification amounts in the preamplifier stage to control the transmission to each of the independent receivers U4a, And U4b, the input signal is within the dynamic range of a particular receiver. Figure 4 illustrates the operation of the switching function of the second stage 144 of Figure 3. In this embodiment, the "gain input" terminal is connected to the output of the high gain amplifier, and the 'low gain input' terminal is connected to the output of the low gain amplifier 1〇6. The basic current source 11 (402) and The current source 12 (404) is alternately turned on to select a high gain path or a low gain path 'to achieve a switching function. Fig. 5 is a schematic diagram showing the front end structure of the third embodiment of the present invention. 〇” has elements similar to those illustrated in FIG. 2, and the elements have similar reference numerals. The front end structure 1 〇〇 is different in that the amplifiers 3 〇 2a and 302b are the same in the third embodiment. however. The input of amplifier 302b is attenuated by the attenuator 3〇4 at the input, thereby reducing the gain of amplifier 302b and increasing the high signal tolerance of amplifier 3〇2b. Another embodiment of the present invention provides a receiver having the above-described front end circuit. The system and method disclosed in accordance with the present invention provides a radio communication receiver such that a plurality of receivers can operate in accordance with individually optimal settings to achieve maximum dynamic range. The system and method provide - front end circuit to make 201134107
得傳送-·-範圍。 同時提供。 ’該路徑最佳化於接Have to transmit -·- range. Also available. 'The path is optimized
本發明之技術内容及技術特點已揭示如上，然而熟悉 本項技術之人士仍可能基於本發明之教示及揭示而作種種 不背離本發明精神之替換及修飾。根據本發明所揭示之系 統和方法可使用於不同的環境中，例如在具有單一輸入的 系統下使用複數個通訊接收器的環境中。據此，該無線通 此外，每一接收器可選擇一路徑， 收器準備處理的信號強度。換言之，赤The technical and technical features of the present invention have been disclosed as above, and those skilled in the art can still make various substitutions and modifications without departing from the spirit and scope of the invention. The systems and methods disclosed in accordance with the present invention can be used in different environments, such as in an environment where a plurality of communication receivers are used under a system having a single input. Accordingly, the wireless transceiver can also select a path for each receiver to prepare for processing the signal strength. In other words, red
GPS和類似裝置。因此，本發 明之保護範圍應不限於實施例所揭示者’而應包括各種不 月離本發明之替換及修飾，並為隨後之申請專利範圍所涵 蓋。 【圖式簡單說明】 下列圖式顯示本發明之數個實施例。藉由參照前述說 明及下列圖式以解釋本發明之原理。熟悉本項技術之人士 應瞭解圖式顯示的特定實施例僅具代表性，因此，本發明 之保護範圍不應受限於所示之實施例。 圖1顯示一傳統的雙接收器之方塊示意圖； 圖2續示本發明第一實施例之前端結構之示意圖； 圖3繪示本發明第二實施例之前端結構之示意圖； 201134107 圖4例示圖3中的第二級之切換功能之運作方式；以及 圖5繪示本發明第三實施例之前端結構之示意圖。 【主要元件符號說明】 10 雙接收器 12 天線 14 可程式化放大器 18 接收器前端 20 接收器子系統 22a, 22b 混波器 24a, 24b 放大器 26a, 26b 輸出信號 100 前端結構 102 天線 103 放大區或农減區 104 放大器 105 切換機制區 106 放大器 107 接收子系統區 110a, 110b 混波器 112a, 112b 放大器 114a, 114b 山 m 100' 前端結構 102' 天線 104，，106' 放大器 110a', 110b' 混波器 11 201134107 112a，，112b' 放大器 114a', 114b' 輸出 142 第一級 144 第二級 146 其他級 202, 204, 放大器 206, 208 100" 前端結構 102" 天線 108a", 108b" 切換機制 110a", 110b" 混波器 112a", 112b" 放大器 302a, 302b 放大器 304 衰減器 402, 404 電流源 12GPS and similar devices. Therefore, the scope of the present invention is not to be construed as being limited to the details of the invention, and the invention is intended to cover various alternatives and modifications. BRIEF DESCRIPTION OF THE DRAWINGS The following drawings show several embodiments of the invention. The principles of the invention are explained by reference to the foregoing description and the following drawings. Those skilled in the art should understand that the specific embodiments shown in the drawings are merely representative and, therefore, the scope of the invention should not be limited to the illustrated embodiments. 1 is a block diagram of a conventional dual receiver; FIG. 2 is a schematic diagram of a front end structure of a first embodiment of the present invention; FIG. 3 is a schematic view showing a front end structure of a second embodiment of the present invention; The operation mode of the switching function of the second stage in 3; and FIG. 5 is a schematic view showing the structure of the front end of the third embodiment of the present invention. [Main component symbol description] 10 dual receiver 12 antenna 14 programmable amplifier 18 receiver front end 20 receiver subsystem 22a, 22b mixer 24a, 24b amplifier 26a, 26b output signal 100 front end structure 102 antenna 103 amplification area or Agricultural Subtraction Area 104 Amplifier 105 Switching Mechanism Area 106 Amplifier 107 Receive Subsystem Area 110a, 110b Mixer 112a, 112b Amplifier 114a, 114b Mountain m 100' Front End Structure 102' Antenna 104, 106' Amplifier 110a', 110b' Mixed Waver 11 201134107 112a,, 112b' Amplifier 114a', 114b' Output 142 First stage 144 Second stage 146 Other stages 202, 204, Amplifier 206, 208 100" Front end structure 102" Antenna 108a", 108b" Switching mechanism 110a" ;, 110b" Mixer 112a", 112b" Amplifier 302a, 302b Amplifier 304 Attenuator 402, 404 Current Source 12